Climacteric Japanese plums were harvested at six developmental stages with no intermediate storage period, and cell wall compositional changes were analyzed. Arabinose proved to be the principal neutral monosaccharide constituent in cell walls during growth and the most dynamic neutral sugar in pectic fractions. Arabinose loss from tightly bound pectins was found to be a relatively early feature in the sequence of cell wall biochemical modifications, thus suggesting a softening-related role during Japanese plum on-tree ripening. Depolymerization of matrix glycans started at the end of the cell expansion phase and increased throughout ripening. Pectin solubilization was first detected during early ripening. Firmness loss did not correlate with polyuronide depolymerization early in ripening, but the last softening phase was associated with a strong depolymerization of cell wall polyuronides as well as a decrease in the arabinose/galactose ratio in loosely bound pectins. This is the first work that characterizes the temporal sequence of cell wall polysaccharide changes in Japanese plum.

No abstract

While peach tree is very sensitive to waterlogging, there are no works on the effect of the flooding over only part of its root system. The objective of this work was to investigate physiological and growth responses of Nemared rootstock to partial flooding of roots. Treatments were performed for 6-days: control trees, half-flooded, and fully-flooded. Both flooding treatments negatively affected the vegetative growth, stomatal conductance, chlorophyll content and leaf water potential. The response observed in the half-flooded treatment was intermediate between the control and fully-flooded treatment. The fastest response of stomatal conductance to soil flooding, before differences among treatments in leaf water potential were perceived, suggested that there should be a stomatal closure mechanism that responds to a signal that arises from flooded roots. The importance of this work, lies in showing the negative effects of unnoticed and partial floods, frequently occurring in peach trees.